Answer:
Sensation to the external nose is mediated through branches of the ophthalmic and maxillary divisions of the trigeminal nerve. The skin at the radix and cephalic sidewalls is supplied by the supratrochlear and infratrochlear nerves. The external nasal branch of the anterior ethmoidal nerve emerges between the nasal bone and the upper lateral cartilage and supplies the skin over the dorsum and down to the tip. Sensation to the lower half and base of the nose is supplied by the infraorbital branch.
1% lidocaine with epinephrine 1:100,000 is injected in small increments in the following sequence: (1) intranasal insertion toward the infraorbital foramen (infraorbital vessels), then parallel to the nasofacial groove (angular vessels) and below the alar base (superior labial vessels); (2) dorsum is infiltrated under the skin (supratrochlear), then under the mucosa (anterior ethmoidal vessels); and (3) minute amounts along the incisions. If septal work is being done, the septal mucosa is injected and the nose is packed with gauze soaked with 2% lidocaine (or 5% cocaine).